The pulsating lambda Bootis star HD 105759

We present spectroscopic and multisite time series photometric observations of the star HD 105759 which confirm that this is a new pulsating lambda Bootis star. Our spectroscopy indicates an overall metallicity of [Z]=log Z-log Z_solar=-1 and that T_eff=8000+/-300 K and logg=4.0+/-0.2. The photometric data reveal that this star pulsates with at least five frequencies: 8.62, 12.69, 20.15, 21.27 and 23.66 d^-1. These frequencies do not all match those found in an earlier single-site study, indicating that the pulsation spectrum changes with time.